#include <iostream>
#include <string>
using namespace std;

int main()
{
	string s;
	s.push_back('h');
	s.push_back('o');
	s.push_back('l');
	s.push_back('o');
	cout << s << endl;
	
	string s1 = "world ! ";
	s1.push_back('h'); 
	s1.push_back('i');
	cout << s1 << endl; 
	
	char it = '0';
	for(it='a';it<='z';it++)
	{
		s1.push_back(it);
	}
	cout << s1 << endl;
	return 0;
 } 
